Support ray-traced rendering of light widget/representation

Interaction/Widgets/vtkLightRepresentation.cxx

@@ -332,6 +332,21 @@ int vtkLightRepresentation::RenderTranslucentPolygonalGeometry(vtkViewport* v)
   return count;
 }
 
+//------------------------------------------------------------------------------
+void vtkLightRepresentation::GetActors(vtkPropCollection* pc)
+{
+  if (pc != nullptr && this->GetVisibility())
+  {
+    pc->AddItem(this->SphereActor);
+    pc->AddItem(this->LineActor);
+    if (this->Positional)
+    {
+      pc->AddItem(this->ConeActor);
+    }
+  }
+  this->Superclass::GetActors(pc);
+}
+
 //------------------------------------------------------------------------------
 void vtkLightRepresentation::PrintSelf(ostream& os, vtkIndent indent)
 {

Interaction/Widgets/vtkLightRepresentation.h

@@ -134,6 +134,13 @@ public:
   int RenderTranslucentPolygonalGeometry(vtkViewport* viewport) override;
   ///@}
 
+  /**
+   * These methods are necessary to make this representation behave as
+   * a vtkProp (i.e., support rendering).
+   * GetActors adds all the internal props used by this representation to the supplied collection.
+   */
+  void GetActors(vtkPropCollection*) override;
+
 protected:
   vtkLightRepresentation();
   ~vtkLightRepresentation() override;